SCS is a type of neurostimulation primarily intended to manage chronic pain, particularly within the back, neck, arms or legs. Benefits of SCS or other forms of neurostimulation may include: a reduction in pain; a reduction or elimination of the use of pain medications; and increased activity levels and an improved overall quality of life. Neurostimulation has been used to manage pain from failed back surgery syndrome or post-laminectomy syndrome and other neuropathies. To this end, an SCS system may be implanted within the body to deliver electrical pulses to nerves along the spinal cord. The SCS system typically includes a small generator device similar to a pacemaker but equipped to send electrical pulses to leads mounted along nerves near the spinal cord. The generator is usually implanted in the abdomen or buttock area. The stimulation leads may include thin wires or paddles for delivering electrical pulses to the nerves along the spinal cord. Thin wire leads, also referred to as percutaneous leads, may be implanted within the epidural space. Paddle leads are instead typically implanted during a surgical procedure where a small amount of bone is removed from one or more of the vertebra. An external controller, similar to a remote control, is provided to allow the patient to control or adjust the neurostimulation.
Although SCS devices are primarily intended to address pain, it would be desirable to enable such devices to also address cardiovascular disorders such as atrial or ventricular arrhythmias, ischemia or heart failure. At least some SCS systems have been developed for use with implantable cardiac rhythm management devices (CRMDs) for monitoring and addressing cardiac health. See, for example, the systems and techniques described in: U.S. Pat. No. 8,706,239 of Bharmi et al., filed May 31, 2012, entitled “Systems and Methods for Controlling Neurostimulation based on Regional Cardiac Performance for use by Implantable Medical Devices ” See, also, systems and techniques described in: U.S. Publication No. 2013/0268016 of Xi et al., filed Apr. 9, 2012, entitled “Systems and Methods for Controlling Spinal Cord Stimulation to Improve Stimulation Efficacy for use by Implantable Medical Devices.” Still further, see, U.S. Patent Publication 2006/0095081 of Zhou et al., entitled “Methods and Apparatus for Sensing Cardiac Activity via Neurological Stimulation Therapy System or Medical Electrical Lead.”
It would be desirable to provide improved systems and techniques for controlling SCS based on cardiac signals, particularly systems and techniques that need not be used in conjunction with a CRMD, and at least some of the aspects of the present invention are directed to that general end.